private void PopAndSetResult(InvocationAndState result)
{
_invocationStack.Pop();
var prevFrame = _invocationStack.Peek();
prevFrame.Invocations.AddLast(result);
}
protected override Expression VisitInvocation(InvocationExpression node)
{
if (_state == RecursionState.Check)
{
Push();
var rewritten = (InvocationExpression)base.VisitInvocation(node);
var frame = _invocationStack.Peek();
var freeCount = 0;
var dqCount = 0;
var candidateCount = 0;
foreach (var invocation in frame.Invocations)
{
if (invocation.State == InvocationSubtreeState.Disqualified)
{
dqCount++;
}
else if (invocation.State == InvocationSubtreeState.Free)
{
freeCount++;
}
else
{
candidateCount++;
}
}
if (frame.DelegationTargets.Count == 0)
{
if (frame.Invocations.Count == freeCount)
{
PopAndSetResult(InvocationAndState.CreateFree());
return(rewritten);
}
else if (candidateCount == 1 && dqCount == 0)
{
var candidate = frame.Invocations.Single(i => i.State == InvocationSubtreeState.Candidate).DelegationTarget;
var target = _delegatableTargets[candidate];
if (target.CanDelegate(candidate, rewritten))
{
PopAndSetResult(InvocationAndState.CreateCandidate(candidate));
return(rewritten);
}
else
{
var delegated = RewriteInvocations(rewritten);
PopAndSetResult(InvocationAndState.CreateDisqualified());
return(delegated);
}
}
else
{
var delegated = RewriteInvocations(rewritten);
PopAndSetResult(InvocationAndState.CreateDisqualified());
return(delegated);
}
}
else if (frame.DelegationTargets.Count > 1)
{
var delegated = RewriteInvocations(rewritten);
PopAndSetResult(InvocationAndState.CreateDisqualified());
return(delegated);
}
else
{
if (frame.Invocations.Count == freeCount)
{
var candidate = frame.DelegationTargets.Single();
var target = _delegatableTargets[candidate];
if (target.CanDelegate(candidate, rewritten))
{
PopAndSetResult(InvocationAndState.CreateCandidate(candidate));
return(rewritten);
}
else
{
var delegated = RewriteInvocations(rewritten);
PopAndSetResult(InvocationAndState.CreateDisqualified());
return(delegated);
}
}
else
{
var delegated = RewriteInvocations(rewritten);
PopAndSetResult(InvocationAndState.CreateDisqualified());
return(delegated);
}
}
}
else
{
var currFrame = _invocationStack.Peek();
var currInvocation = currFrame.Invocations.First();
currFrame.Invocations.RemoveFirst();
if (currInvocation.State == InvocationSubtreeState.Candidate)
{
var candidate = currInvocation.DelegationTarget;
var target = _delegatableTargets[candidate];
return(target.Delegate(candidate, node));
}
else
{
return(node);
}
}
}